title: Imaging of upper urinary tract cancer: using conventional MRI and diffusion-weighted MRI with different b values.
abstract: BACKGROUND
  Diffusion-weighted magnetic resonance imaging (DW-MRI) has been considered to be useful in diagnosing upper urinary tract (UUT) disease; however, the value of DW-MRI with different b values has not been reported.
  
  
  OBJECTIVE
  To evaluate the performance of using conventional MRI alone and in combination with DWI with different b values in diagnosing UUT cancer.
  
  
  METHODS
  Seventy patients with suspected UUT cancer underwent conventional MRI (T1-weighted and T2-weighted) and DW-MRI (b = 500 and 1500 s/mm(2)) on a 3 T-MRI scanner. The ureteroscopic and histopathologic findings were compared with the imaging findings. The utility of detecting UUT cancer using conventional MRI (set A), combined DW-MRI (b = 500 s/mm(2)) and conventional MRI (set B), and combined DW-MRI (b = 1500 s/mm(2)) and conventional MRI (set C) were independently evaluated by two readers.
  
  
  RESULTS
  A total of 32 patients had verified cancer; 23 patients had benign UUT diseases, and 15 had no abnormality. Sets B and C had significantly improved diagnostic accuracy for UUT cancer compared with set A; the specificity in diagnosing UUT cancer was significantly improved when using set C compared with sets A and B. In patients without UUT obstructions, improved sensitivity and accuracy in diagnosis was achieved when using sets B and C compared with set A.
  
  
  CONCLUSIONS
  Using DW-MRI in combination with conventional MRI provides increased diagnostic accuracy and sensitivity in patients without UUT obstruction. The combination of conventional MRI and DW-MRI with a higher b value (1500 s/mm(2)) improved the specificity in diagnosing UUT cancer compared to conventional sequences and DW-MRI with a lower b value (500 s/mm(2)).
authors.affiliation: Department of Radiology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, PR China.
authors.forename: Guang-Yu
authors.initials: GY
authors.lastname: Wu
authors.affiliation: Department of Radiology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, PR China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Lu
authors.affiliation: Department of Radiology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, PR China.
authors.forename: Lian-Ming
authors.initials: LM
authors.lastname: Wu
authors.affiliation: Department of Urinary Surgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, PR China.
authors.lastname: WenKong
authors.affiliation: Department of Radiology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, PR China.
authors.forename: Xiao-Xi
authors.initials: XX
authors.lastname: Chen
authors.affiliation: Department of Radiology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, PR China renjixujr@163.com.
authors.forename: Jian-Rong
authors.initials: JR
authors.lastname: Xu
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007680:Kidney Neoplasms / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014516:Ureteral Neoplasms / Q000473:pathology*; D018666:Ureteroscopy
keywords: Magnetic resonance imaging (MRI); b value; diagnosis; differential diagnosis; diffusion-weighted imaging (DW-MRI); upper urinary tract (UUT) cancer